Patent US4276641A successfully refreshed from Google Patents.
Patent EP0121072A2 successfully refreshed from Google Patents.
EP0121072A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for accessing a data set in a word processing system
Assignee: International Business Machines Corp
•
Filing: 1984-02-20
•
Granted: —
•
Expires: 2004-02-20
Abstract
Abstract A word processing system (10) is disclosed in which a text stream is stored on a direct access storage device (DASD) (22) for recall and editing..The text stream is organized into a document, which is stored on the DASD as a data set. The data set consists of an index portion and a portion containing text records. The index portion is divided into nodes, of which the primary node is called the root node. When the system operator designates a data set for use, the root node is fetched and retained in a system memory (26, 50) to eliminate the need to fetch it from the DASD (22) for every access. When sequential records are accessed, such as during a document duplication operation, the index is fully searched only for the first of the sequential records. Subsequent records are located through the index node(s) already in the system memory (26), with subsequent index nodes being fetched from the DASD only when the last index entry in the current index node (62) has been processed. When sequential records are written to the DASD, the index is fully searched only for the insertion point for the first record. For subsequent records, the same index node (62) is updated until there is insufficient room for index entry for the latest record written to the DASD. At that time the index node is split and index entries at higher levels (50) of the index are updated in a similar manner.
Inventors
- 👤 John A. Aiken, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 10:17
CPC Classifications
G; G06; G06F; G06F16/00; G06F16/90; G06F16/901; G06F16/9017
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
173 words
In a word processing system (10) including a system memory (26) and a direct access storage device (22) storing an input text stream where said text may be selected later for revision, a method for accessing a data set in the word processing system comprising the steps of: performing an open data set for access operation (350-367) by first searching (330-341) the current volume index on the DASD (22) for a desired data set based on the data set name and the data set type; characterized by: fetching (360) the data set index root node (170, 200, 240) into an interface control block (50, 306) in the system memory (26) called a storage access control block; requiring and providing the storage access control block (306) to remain available at the same memory location for all subsequent accesses to the data set until a close data set operation is performed; and using (331) the root node stored in the storage access control block for all subsequent searches and updates to the data set index.
Claim 2
Dependent Claim
173 words
In a word processing system (10) including a system memory (26) and a direct access storage device (22) storing an input text stream where said text may be selected later for revision, a method for accessing a data set in the word processing system comprising the steps of: performing an open data set for access operation (350-367) by first searching (330-341) the current volume index on the DASD (22) for a desired data set based on the data set name and the data set type; characterized by: fetching (360) the data set index root node (170, 200, 240) into an interface control block (50, 306) in the system memory (26) called a storage access control block; requiring and providing the storage access control block (306) to remain available at the same memory location for all subsequent accesses to the data set until a close data set operation is performed; and using (331) the root node stored in the storage access control block for all subsequent searches and updates to the data set index.
Claim 3
Dependent Claim
159 words
A storage access method according to claim 1 further comprising the steps of: requiring each index node of a data set not to exceed a specified maximum length when updating the data set index for the inclusion of additional records or pages to the existing data set; requiring the root node of a data set index to be the unique index node at the highest existing level of said index; requiring each index node to contain index entries of either individual pages and records of the data set or of next lower level index nodes; constructing (520-535) an additional next-to-highest index level where necessary to prevent the said root node from growing beyond the said maximum length specification; splitting (540-558) a non-root level index node where necessary to prevent such node from growing beyond the said maximum length specification; and updating and inserting (550-556) as necessary any higher level index nodes when some lower level index node is split.
Claim 4
Dependent Claim
111 words
A storage access method according to claim 2, characterized by: fetching (333) a lower level index node (202, 204, 244, 246, 256, 258, 260) into an index node buffer (286, 288, 290) of an internal control block (62, 280) in the system memory (26) when called for by an index entry found in a higher level node; and using (331, 400) the said lower level index node stored in said index node buffer of the internal control block for all subsequent searching of or sequential accessing to the index entries contained within said index node as long as said stored index node does not have to be replaced in said buffer.
Claim 5
Dependent Claim
145 words
A storage access method according to claim 3, further characterized by the steps of: providing a chain (206, 210) of index entries (217, 218, 220, 222) for the adjacent index nodes (if any) of equal level, within each node (202, 204) of non-root level, or at least within the lowest index level called the leaf node level; using (405, 409) the chained index entries of an index node stored in a said index node buffer for access to a next index node of same level in any sequential access operations going beyond the index entries contained within said stored node, whereby a renewed access of and search in higher level nodes is superfluous; and updating (547, 548) as necessary said chained index entries contained in the adjacent nodes (if any) of some stored index node of non-root level when said stored node is being split.
Claim 6
Dependent Claim
83 words
A storage access method according to any preceding claim further comprising the steps of: requiring the root node of a data set index to contain an entry providing a data set profile (172) comprising the data set name (176) and a data set comment (178); and checking (361) the data set name (176) from the expected root node of a desired data set as soon as said root node is fetched (360) into a storage access control block (306) in system memory (26).
Claim 7
Dependent Claim
185 words
A storage access method according to any preceding claim, further comprising the steps of: including (482) a key information field (146, 148, 150, 186, 192) within each page or record index entry (140, 142, 144, 182, 184) contained in any index node at the leaf level of a data set index; including (507-515) a high key information field (186, 228) within each leaf node index entry (224, 232) contained in any non-leaf level index node, where a such high key value corresponds to the highest value among the keys of the pages or records for which index entries are found in the leaf node pointed to by said leaf node index entry; and inserting (490-515) page or record index entries for any additional- . pages or records of the data set only in selected positions of selected leaf index nodes such that keys of sequential page or record index entries appear in an ascending sequence within each leaf node as well as through all leaf nodes, whereby efficient search operations by key values of desired pages or records are feasible through the data set index.
Claim 8
Dependent Claim
78 words
A storage access method according to claim 3, including the step of: providing a-plurality of index node buffers (286, 288, 290) within said internal control block (280) sufficient in number to accommodate any index node operations as required for inserting additional record, page, leaf or intermediate index entries, constructing sub-root level index nodes, splitting a sub-root index node, or any other updating of data set index, and searching or sequential accessing in index nodes of any sub-root level.
Claim 9
Dependent Claim
202 words
In a word processing system where a text stream is stored on a direct access storage device (DASD) such as diskette or hard disk, a method for improving the performance of subsequent read access of sequential records within a data set, comprising the steps of: determining a maximum count of the number of records to be processed with a single request to the storage access method routines, based on whether the multiple-records processing option was requested or not; locating the index node and the index entry for the first record to be processed; reading said record into a user buffer, performing buffer length checking and transfer of the record key in the case where said record is the first record of a page; locating the next record index entry in said current index node, or locating and reading the next index node and locating the first index entry of said next index node as the next record index entry; and comparing the actual number of records processed during said request to said storage access method routines, terminating said request when said maximum number of records has been processed or when said record buffer contains insufficient space to contain the entire next record.
Claim 10
Dependent Claim
202 words
In a word processing system where a text stream is stored on a direct access storage device (DASD) such as diskette or hard disk, a method for improving the performance of subsequent read access of sequential records within a data set, comprising the steps of: determining a maximum count of the number of records to be processed with a single request to the storage access method routines, based on whether the multiple-records processing option was requested or not; locating the index node and the index entry for the first record to be processed; reading said record into a user buffer, performing buffer length checking and transfer of the record key in the case where said record is the first record of a page; locating the next record index entry in said current index node, or locating and reading the next index node and locating the first index entry of said next index node as the next record index entry; and comparing the actual number of records processed during said request to said storage access method routines, terminating said request when said maximum number of records has been processed or when said record buffer contains insufficient space to contain the entire next record.
Claim 11
Dependent Claim
237 words
In a word processing system where a text stream is stored on a direct access storage device (DASD) such as diskette or hard disk, a method for improving the performance of subsequent write access of sequential records within a data set, comprising the steps of: determining a maximum count of the number of records to be processed with a single request to the storage access method routines, based on whether the multiple-records processing option was requested or not; locating the index node and the index entry for the first record to be processed; writing said record from the user buffer onto the storage volume; inserting an index entry for said record into said index node, taking into account whether said record is the first record of a page and taking into account whether said index node contains sufficient space to insert said new index entry; dividing said current index node into one or two other index nodes in order to make room for said new index entry; repeating said steps for creation of a new index entry and insertion at a higher-level node of the data set index until insertion is accomplished without split of said higher-level index or until the data set root node has been updated; and comparing the actual number of records processed during said request to said storage access method routines, terminating said request when said maximum number of records has been processed.
Claim 12
Dependent Claim
237 words
In a word processing system where a text stream is stored on a direct access storage device (DASD) such as diskette or hard disk, a method for improving the performance of subsequent write access of sequential records within a data set, comprising the steps of: determining a maximum count of the number of records to be processed with a single request to the storage access method routines, based on whether the multiple-records processing option was requested or not; locating the index node and the index entry for the first record to be processed; writing said record from the user buffer onto the storage volume; inserting an index entry for said record into said index node, taking into account whether said record is the first record of a page and taking into account whether said index node contains sufficient space to insert said new index entry; dividing said current index node into one or two other index nodes in order to make room for said new index entry; repeating said steps for creation of a new index entry and insertion at a higher-level node of the data set index until insertion is accomplished without split of said higher-level index or until the data set root node has been updated; and comparing the actual number of records processed during said request to said storage access method routines, terminating said request when said maximum number of records has been processed.
Claim 13
Dependent Claim
143 words
LO. Apparatus for improving the performance of accessing and updating a data set in a word processing system where a text stream is stored on a direct access storage device (DASD) such as diskette or hard disk and where said text may be selected later for revision, comprising: means for searching the current volume index for the desired data set, based on data set name and data set type; means for fetching the data set root (first index element node) into an interface control block called a storage access control block (sacb); means for requiring the sacb to remain available at the same memory location for all subsequent accesses to the data set until a close data set operation is performed; and means for using the root node stored in the sacb for all subsequent searches and updates to the data set index.
Claim 14
Dependent Claim
143 words
LO. Apparatus for improving the performance of accessing and updating a data set in a word processing system where a text stream is stored on a direct access storage device (DASD) such as diskette or hard disk and where said text may be selected later for revision, comprising: means for searching the current volume index for the desired data set, based on data set name and data set type; means for fetching the data set root (first index element node) into an interface control block called a storage access control block (sacb); means for requiring the sacb to remain available at the same memory location for all subsequent accesses to the data set until a close data set operation is performed; and means for using the root node stored in the sacb for all subsequent searches and updates to the data set index.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.